Improvement in steam-engine exhaust-valves



"te idem/tl agraire @am Letters PatentpNo. 85,289, dated December 29,1868 lmtedcted December 23, v186e'.

IMPROVBNIENT IN STEAM-ENGINE EXHAUST-VALVES.

The Schedule referred to in these Letters Patent and making part of thesame.

* o-OrFw- To all persons to whom these 'presents shall come Be it knownthat I, THOMAS S. Davrs, of Jersey City, in the county of Hudson, andState of New Jersey, have invented a new and improved Attachment to orConstruction ofthe ExhaustPassages to Engines and that the followingdescription, taken in connection with tlie accompanying plate ofdrawings, hereinafter referred to, forms a full and'completespecification of the same, wherein I have set forth the nature andprineiples of my said improvement, by which my invention may bedistinguished from all others of a similar class, together with suchparts as -I claim, and desire to have secured to me by Letters Patent.

The principal object of the present invention is .to prevent the accessor passage, through the exhaust or eduetion-ports or passages oflocomotive oi' other engines, to the valvechests and cylinders of thesame, 'of cinders, heated air, and other. detrimental matter; and,for-this purpose,

The invention consists in the arrangement, within` the exhaust oreduction-ports or passages of locomotive or other engines, and at. anypoint or points of their length, of a valve or valves, whereby they canfreely open,` to allow the exhaust-steam to escape from the cylinder,and close the moment the pressure withinzthe cylinder becomes equal toor less than that of the at mosphere within'the smoke-box, so that theentrance of all deleterious matter, such as cinders, heated air,.

86e., to the cylinder or the valve-chest is eii'eetually and entirelyprevented.

.In t-he accompanying plate of drawings, my improved arrangement of theexhaustepassages to engines is illustrated- Figure l being an elevationof the portion of an exhaast-passage having a valve arranged in itaccording to the present invention;

Figurev 2, a plan or top view of the exhaust-passage shown in iig. l;and

Figure 3, a vertical section, taken in the plane of the line :c iig. l.Q

A, in the drawings, represents an exhaust-passage or tube.

This tube A, at its lower end, is provided with two openings or ports,one alongside of the other, to which pipes or tubes, shown in red linesin the drawings, are to be attached, for forming a connection betweenthe passage A and the exhaust-ports of the steam or piston-cylinder toan engine. v i

`The upper end, A2, of' the tube A, when placed in position upon alocomotive-engine, is arranged thereon so as to open into thesmoke-chamber of the same, and thus allow the exhaust-steam, passingthrough the said tube from the cylinder, to escape into the saidchamber.

B, a dislevalve, having a centre-stem, c.

This valve B is within the tube A, and, at D, is provided with a seat,E, for it to rest upon, and, above such seat, 'with a fixed cross-bar,F, for its stem to play 'heated air, or other deleterious mattei', tothe cylinder or `valve-chest, the valve being only arranged to openupward, for the passage of the exhaust-steam to the -With a valvearranged for operation within the exhaust-passage of an engine,substantially as above described, it is plainly apparent that, while butlittle obstruction is given to the escape of the exhaust-steam from thecylinder, the entrance of cinders, smoke, coal` dust, heated air, orother deleterious mattei' from the smoke-chamber, to the cylinder orvalvechest is entirely and effectually prevented, a result ofthe utmostimportance and'advantage in the running of a locomotive-engine moreparticularly, as, for instance, when the engine is running without steamin the cylinders, and by Aits previous acquired momentum, or when theengine lis reversed, in order tol stop quickly, for thereason that, insuch cases, without-the said val ve, there.

wouldvbe no hindrance to the passage of cinders, Sac., from thesmoke-chamber to the cylinder and valvechest, which einders, &c., beinggritty, would cause great injury'to the,pistons and valves, as welll asto the cylinders and valve-chests, 4finally destroying and renderingthem useless.'

And it may be here observed that, while the safetyvalves of mostlocomotive-engines are suiicient for all ordinary purposes andoccasions, they are greatly defeotive in this respect: that they allow,even when wide open, the pressure in the boiler to accumulate to afearful extent at times, as, for instance, when the engine, with a heavytrain, is moving over a down grade, and it becomes absolutely necessary,for safety, to cheek the speed ofthe train by reversing the engine; for,if then the pressure upon the pistons be not suiicient to hold thedriving-wheels, or to turn them backwards, the air from the smoke-box isnecessarily pumped into the boiler, thus'raising the pressure thereinmuch faster than the safety-valves are able to relieve it, and, as aconsequence, either exploding the boiler or collapsing the tubes, thelatter. more 'generally being the result. This effect, as is obvious, isa source of great annoyance and expense to roads that have heavygradesfand necessarily heavy engines to run their trains; and, con`-sequent/ly, in lieu of reversing the engine, the engineers generallydepend upon the ordinary brakes of the cars to retard or hold the train,which are not only complicated, but expensive in arrangement, while, ifthe engine could be reversed without danger of exploding the boiler orcollapsing the tubes, no better or more perfeet'and sure brake could behad; and by my invention, as is manifest, the engine is so enabled to beemployed, without the least danger thereto or to its boiler,

as the inward passage or pumping of the heated wir, 85o., from thesmoke-box cannot possibly occur, but is entirely prevented.

In addition to the several`znlvzn1tages ztnd results above stated assecured by my invention, it may be well to here observe that, as anotherconsequence of the exclusion of gritty particles, heated air, Sie., fromthe cylinders and valve-chests of an engine, less oil is required to beemployed to keep the cylinders, Ste., lnbxicated, as the full e'ectofthe steam, for sncb purposes, is secured, (steam being well known tobe :t suicient lubrieator therefor) thus reduci n g, in that respect,the expense oi' running the engine.

By tlle'arrengement ofthe valve B, above described, it is left free toclose by its own gravity, or by the pressure of the :atmosphere withinthe smoke-box but springs may be employed in connection with it, if sodesired.

In locating the valve within Vthe exhaust-passage, l'

prefer, for convenience, to `place it at the extremity oi"

